1. Field of the Invention
This invention relates to improvements to air conditioning and heating equipment, and particularly to air distribution ducting and plenums.
2. Description of Related Art
Conventional indoor central air conditioning and heating equipment comprises a blower which forces air through a heat exchanger, all contained within one or more cabinets coupled between an air intake and distribution ducting. Typically, a final chamber, or plenum, is coupled to the outfall of the last cabinet, and one or more ducts extend to remote registers where air is expelled into the living space, eventually to return to the central air intake.
The plenum typically comprises a box open at one end to the cabinet and closed at the opposite end. The plenum is sized to match the outfall of the cabinet and to create a chamber in which conditioned air is pressurized by the air handler for distribution. The plenum and duct lines usually are composed of insulated duct board or sheet metal and flexible duct, both having a metalized skin to minimize heat transfer to and from the unconditioned spaces of the building, typically an attic, where temperatures more closely match outside conditions.
Conventional plenums typically are fabricated separately and attached to the cabinet outfall during construction. Sometimes fabricated at the building site, more commonly they are prefabricated elsewhere and shipped, sometimes for significant distances. Being mostly empty boxes, they occupy significant space relative to their weight, especially when multiple plenums are shipped and/or held together for inventory. A need exists for an efficient means for storage and shipping of prefabricated plenums.
Indoor air conditioning and heating equipment often is installed in relatively inaccessible places. During construction, for example, the equipment may be moved into an attic space before the roof or ceiling is installed. Once the roof and ceiling both are in place, a relatively small access door may severely restrict the installer's ability to move bulky objects to the attic. A need exists for a collapsible plenum which more easily may be transported into tight spaces and then expanded for use.